Nodedefinitions are specified using tables (see Table 2).

Attributesare defined by providing the Attributename and a value, or a description of the value.

Referencesare defined by providing the ReferenceTypename, the BrowseNameof the TargetNodeand its NodeClass.

  • If the TargetNodeis a component of the Nodebeing defined in the table, the Attributesof the composed Nodeare defined in the same row of the table.
  • The DataTypeis only specified for Variables; "[<number>]" indicates a single-dimensional array, for multi-dimensional arrays the expression is repeated for each dimension (e.g. [2][3] for a two-dimensional array). For all arrays the ArrayDimensionsis set as identified by <number> values. If no <number> is set, the corresponding dimension is set to 0, indicating an unknown size. If no number is provided at all the ArrayDimensionscan be omitted. If no brackets are provided, it identifies a scalar DataTypeand the ValueRankis set to the corresponding value (see OPC 10000-3). In addition, ArrayDimensionsis set to null or is omitted. If it can be Any or ScalarOrOneDimension, the value is put into "{<value>}", so either "{Any}" or "{ScalarOrOneDimension}" and the ValueRankis set to the corresponding value (see OPC 10000-3) and the ArrayDimensionsis set to null or is omitted. Examples are given in Table 1.

Table 1– Examples of DataTypes









omitted or null

A scalar Int32.




omitted or {0}

Single-dimensional array of Int32 with an unknown size.




omitted or {0,0}

Two-dimensional array of Int32 with unknown sizes for both dimensions.





Two-dimensional array of Int32 with a size of 3 for the first dimension and an unknown size for the second dimension.





Two-dimensional array of Int32 with a size of 5 for the first dimension and a size of 3 for the second dimension.




omitted or null

An Int32 where it is unknown if it is scalar or array with any number of dimensions.




omitted or null

An Int32 where it is either a single-dimensional array or a scalar.

If the NodeIdof a DataTypeis provided, the symbolic name of the Noderepresenting the DataTypeshall be used.

Nodesof all other NodeClassescannot be defined in the same table; therefore only the used ReferenceType, their NodeClassand their BrowseNameare specified. A reference to another part of this document points to their definition.

Table 2illustrates the table. If no components are provided, the DataType, TypeDefinition and ModellingRule columns may be omitted and only a Comment column is introduced to point to the Nodedefinition.

Each Nodedefined in this specification has ConformanceUnitsdefined in OPC 10000-7that require the Nodeto be in the AddressSpace. If a Serversupports a ConformanceUnit, it shall expose the Nodesrelated to the ConformanceUnitin its AddressSpace. If two Nodesare exposed, all Referencesbetween the Nodesdefined in this specification shall be exposed as well.

The relations between Nodesand ConformanceUnitsare defined at the end of the tables defining Nodes, one row per ConformanceUnit. The ConformanceUnitis reflected with a Category element in the UANodeSetfile (see OPC 10000-6).

The Nodesdefined in a table are not only the Nodedefined on top level, for example an ObjectType, but also the Nodesthat are referenced, as long as they are not defined in other tables. For example, the ObjectType ServerTypedefines its InstanceDeclarationsin the same table, so the InstanceDeclarationsare also bound to the ConformanceUnitsdefined for the table. The table even indirectly defines additional InstanceDeclarationsas components of the top-level InstanceDeclarations, that are not directly visible in the table. The TypeDefinitionsand DataTypesused in the InstanceDeclarations, and the ReferenceTypesare defined in their individual tables and not in the table itself, therefore they are not bound to the ConformanceUnitsof the table. As another example, the OrderedListTypereferences the GeneralModelChangeEventType, which is defined in another table, and therefore not bound to the ConformanceUnitsof the table. In case of ambiguity, the Category element of the UaNodeSetfile provides the precise information.

Table 2– TypeDefinition Table



Attribute name

Attribute value. If it is an optional Attribute that is not set "--" will be used.








NodeClassof the TargetNode.

BrowseNameof the target Node.

DataType of the referenced Node, only applicable for Variables.

TypeDefinitionof the referenced Node, only applicable for Variablesand Objects.

Referenced ModellingRuleof the referenced Object.

NOTE Notes referencing footnotes of the table content.

Conformance Units

Name of conformance unit, one row per conformance unit

Components of Nodescan be complex that is containing components by themselves. The TypeDefinition, NodeClass, DataTypeand ModellingRulecan be derived from the type definitions, and the symbolic name can be created as defined in 4.1. Therefore those containing components are not explicitly specified; they are implicitly specified by the type definitions.